A local backup is any backup where the storage medium is kept close at hand. Typically, the storage medium is plugged in directly to the source computer being backed up or is connected through a local area network to the source being backed up.

Advantages

Storage cost can be very cheap when the right storage medium is used like external hard drives

Data transfer cost to the storage medium can be negligible or very cheap

Since the backups are stored close by, they are very conveniently obtained whenever needed for backups and restore.

Full internal control over the backup storage media and the security of the data on it. There is no need to entrust the storage media to third parties.

Disadvantages

Since the backup is stored close by to the source, it does not offer good protections against theft, fire, flood, earthquakes and other natural disasters. When the source is damaged by any of these circumstances, there’s a good chance the backup will be also damaged.